Shift Register Circuit With Bootstrap Bias for Noise-Stable Displays
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Solution Overview
Problem
Conventional shift register circuits in semiconductor devices suffer from malfunctions due to noise, high power consumption, and variations in characteristics, particularly in unipolar transistor-based circuits used in display devices, where the output signal voltage is attenuated and prone to distortion.
Innovation Solution
A semiconductor device with a shift register circuit design that includes specific transistor configurations and rectifying elements to stabilize electric potential, reduce noise, and minimize power consumption, featuring transistors that fix and reverse electric potentials, and a circuit structure that operates with reduced transistor kinds on the substrate, allowing for stable operation and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a unipolar transistor-based shift register circuit is used to simplify manufacturing, then manufacturing complexity is reduced, but output signal voltage is attenuated and the circuit becomes prone to noise malfunctions
Solution Approach 1:
The patent changes the electrical parameters of the circuit by introducing bootstrap capacitors that dynamically adjust the gate-source voltage of transistors during operation. This allows the circuit to maintain proper voltage levels and signal integrity while using unipolar transistors, thereby improving reliability without sacrificing manufacturing simplicity
Solution Approach 2:
The patent introduces bootstrap capacitors as intermediary elements between the power supply and the transistor gates. These capacitors act as mediators that store and release charge to maintain appropriate voltage levels, preventing signal attenuation and noise susceptibility while keeping the transistor structure simple
2Reliability
If conventional bootstrap circuits are used to prevent voltage attenuation, then output voltage stability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic charging and discharging of bootstrap capacitors synchronized with the clock signal cycles. The capacitors are charged during specific phases and discharge during others, providing voltage stabilization only when needed rather than continuous power consumption, thus reducing overall energy usage while maintaining voltage stability
3Reliability
If multiple transistor types are used to achieve proper signal levels, then signal integrity is maintained, but device complexity increases
Solution Approach 1:
The patent maintains signal integrity by dynamically changing the electrical parameters (voltage levels) through bootstrap capacitors rather than using different transistor types. The same unipolar transistor structure is used throughout, but its operating parameters are adjusted in real-time, achieving signal integrity without increasing device structural complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution enables a shift register circuit that operates stably with minimal malfunctions, low power consumption, and reduced characteristic variations, enhancing the reliability and efficiency of semiconductor devices in display applications.
Implementation Method 1
a first transistor (12) for transmitting electric potential of a first terminal (C) to the output terminal (OUT)
Implementation Method 2
a capacitor element (14) which holds electric potential at the second terminal (P)
Data Source
AI summary
To provide a semiconductor device which operates stably with few malfunctions due to noise, with low power consumption, and little variation in characteristics; a display device including the semiconductor device; and an electronic device including the display device. An output terminal is connected to a power supply line, thereby reducing variation in electric potential of the output terminal. In addition, a gate electrode potential which turns ON a transistor is maintained due to the capacitance of the transistor. Further, change in characteristics of the transistor is reduced by a signal line for reverse bias.